A transport network, or transportation network is a realisation of a spatial network, describing a structure which permits either vehicular movement or flow of some commodity. Examples include but are not limited to road networks, railways, air routes, pipelines, aqueducts, and power lines.
Transport network analysis is used to determine the flow of vehicles (or people) through a transport network, typically using mathematical graph theory. It may combine different modes of transport, for example, walking and car, to model multi-modal journeys. Transport network analysis falls within the field of transport engineering. Traffic has been studied extensively using statistical physics methods. Recently a real transport network of Beijing was studied using a network approach and percolation theory. The research showed that one can characterize the quality of global traffic in a city at each time in the day using percolation threshold, see Fig. 1. In recent articles, percolation theory has been applied to study traffic congestion in a city. The quality of the global traffic in a city at a given time is by a single parameter, the percolation critical threshold. The critical threshold represents the velocity below which one can travel in a large fraction of city network. The method is able to identify repetitive traffic bottlenecks.  Critical exponents characterizing the cluster size distribution of good traffic are similar to those of percolation theory. It is also found that during rush hours the traffic network can have a several metastable states of different network sizes and the alternate between these states.
An empirical study regarding the size distribution of traffic jams has been performed recently by Zhang et al. They found an approximate universal power law for the jam sizes distribution.
A method to identify functional clusters of spatial-temporal streets that represent fluent traffic flow in a city has been developed by Serok et al. G. Li et al developed a method to design an optimal two layer transportation network in a city.
Flow patterns of traffic
River-like patterns of traffic flow in urban areas in large cities during rush hours and non rush hours have been studied by Yohei Shida et al
- Braess' paradox
- Flow network
- Heuristic routing
- Interplanetary Transport Network
- Network science
- Percolation theory
- Street network
- Rail network
- Multimodal transport
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- Switch between critical percolation modes in city traffic dynamics, G Zeng, D Li, S Guo, L Gao, Z Gao, HE Stanley, S Havlin, Proceedings of the National Academy of Sciences 116 (1), 23-28 (2019)
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